Ed Yong (@edyong209 on Twitter) is a fabulous British science writer and blogger, who won in 2010 the prestigious National Academies Communication Awards, jointly presented by the National Academy of Sciences, National Academy of Engineering, and Institute of Medicine. His writing has been featured in New Scientist, the Times, WIRED, the Guardian, Nature amongst other places, and he currently blogs (“”http://blogs.discovermagazine.com/notrocketscience" style=“text-decoration: none;”>Not Exactly Rocket Science") at the Discover Magazine website.
Most of my readers here, I expect, already read and follow him. If you haven’t had the pleasure, don’t delay. Ed is a fantastic writer, very readable, and he presents the awe-inspiring and glorious world of science in a lucid enjoyable manner. I follow his blog religiously.
In a recent post, Ed presents a fascinating study – published in PLoS One – about how some blind human beings are able to use the technique of Echolocation; they make clicking noises with their tongue (or with an object like a cane) and – from the rebounding echoes – they are able to estimate not only the presence of objects in their paths, but also the distance, size, shape and texture of those objects. Much in the same way as dolphins and bats do, these people can “see” their world in sound. Daredevil, anyone?
The PLoS One article studied functional brain activities in a couple of sightless individuals, noting activity in a part of the brain called Calcarine Cortex, the area of the brain associated with sight. I don’t want to give it away; please read Ed’s article and the PLoS One paper to know more of this. However, one aspect that I found particularly amazing is that this skill apparently can be taught to other sightless individuals.
My father was a teacher of Music in a local school for blind children which provided them with education as well as vocational training. Amongst the students, there were many types: some were congenitally blind, some lost vision as a result of some life-threatening illness or severe injury, while some had very poor eyesight and would gradually lose it. I always felt particularly bad for this latter group; in my experience, some of these children used to take a leadership position in a class group, guiding and helping others. I can’t imagine what it must feel like to gradually lose vision, and I thought it incredibly brave of these children who would state it as a matter of fact.
Ed’s article presents incredibly good news; it appears that the echolocation technique can be taught and the skill acquired, and that’s exactly what the subjects of the PLoS One study do. Writes Ed:

As leaders of their organisation, World Access for the Blind, they travel the world teaching echolocation (they called it “FlashSonar”) to blind teens and adults, and leading them on activities such as hiking and mountain biking. They have reached over 2,500 people in 18 countries. Kish says, “We expect this to add much creditibility to our own approach to teaching and working with blind students. In this respect, I hope it helps to make me a better Perceptual Mobility Therapist.”

This is amazing! I have seen adult blind individuals walking around with the aid of their foldable walking stick; they would tap the ground ahead of them before placing a foot ahead. But if taught how to echolocate, these people should be able to lead assistance-free, normal lives, engage in regular activities, and not be at risk for getting injured even on busy streets. The possibilities are endless.

4 Comments

Oflate I read a post on brain plasticity and how the cells involved in sight shift to hearing in blind people thereby making them more sensitive to sound as a compensation for loss of sight. Your post added more light on it . Thanks for the article too.

Now onto human echolocation… you may like to watch this video about a boy (Ben Underwood) who has taught himself echolocation. This video shows him skating and doing everything a young boy can ….really amazing!

Thank you for your comments and links, Tej and Laura. The compensation mechanism apparently works for senses other than sight also. My aunt, who is an administrator with the National Institute for the Visually Handicapped in India, told me about a blind artist they have worked with. This artist had trained his sense of smell to be able to accurately tell the time of the day from the smell of certain flowers blooming at specific times.

What the echolocation study I mentioned tells me, additionally, is that even if the compensatory mechanisms make one sense, say, hearing, supreme in the absence of another, say, sight, the area of the brain being stimulated is still the visual ‘calcarine’ cortex. This opens up very interesting possibilities as you can imagine.